A movie's main plot is what drives the story and keeps audiences engaged. However, the best movie subplots are frequently the parts of many films that keep audiences talking, as opposed to the main story arc. Subplots provide depth to a primary plot, and sometimes, even steal the show.
Sure, sometimes a subplot with a bunch of holes can distract from the primary purpose of a film. But the best writers and movie-makers know that dynamic characters can have their own stories, which drive the plot into more exciting directions. Unexplained moments in a movie could leave an audience unsatisfied, but when a film creator knows how to weave a subplot into a film's first story effectively, it creates a more human and engaging movie, whether it's animated or "real life."
Frequently, a subplot could be the aspect of a film that keeps a fan engaged. While the original story usually has the elements of a traditional plot, a great subplot inspires cult followings and analysis years after the release of a successful film.
The 1980s movie, The Princess Bride, is a classic enjoyed by all ages and genders. Like Frozen, even young boys love this film for reasons they can't articulate. And that reason probably has less to do with the appearance of Andre The Giant than they think. Maybe it's the timeless subplot about a man seeking to avenge the death of his father. Inigo Montoya follows the film's primary protagonist, Westley, and he becomes one of Westley's independent side-kicks. However, the moment when Montoya gets to showcase his swordsman skill-set and defeat one of the antagonists of the film, Count Rugen, the man responsible for killing Montoya's father, gets viewers wholly engaged. Montoya's revenge pushes the love story of Westley and Buttercup to the back burner.
While Superbad undoubtedly stands on its own, the subplot involving Fogell's friendship with the police played by Bill Hader and Seth Rogen dominates the film. Superbad is ultimately about the friendship between Seth and Evan. However, when people discuss this movie, it takes approximately 15 seconds before someone screams, "McLovin!" This subplot is a prime example of how a b-story can take over a film.
Snape is an interesting character in the Harry Potter films. His backstory seems to steal the show in Harry Potter and the Half-Blood Prince and the Deathly Hallows. We learn about Snape's struggles fitting in and his love for Harry's mother, Lily. Ultimately, Snape's character had to appear to be bad, so that good could prevail. And that subplot provides another layer of interesting for Harry Potter fans to explore in the Half-Blood Prince and Deathly Hallows.
The Sandlot is a childhood classic for many. The main plot focuses on a group of friends who need to retrieve a Babe Ruth autographed ball from a fierce (well, not really) dog. However, even this great film and its plot seem to get overshadowed by the relationship between Scotty Smalls and Benjamin Franklin Rodriguez. The all-star athlete Rodriguez mentors Smalls and offers the lonely unathletic kid friendship when he needs it the most. In return, Smalls is a lifetime fan of Rodriguez, and roots on Rodriguez after the baseball player makes it to the "big leagues."